broad slipped in his delivery stride and was left clutching left ankle .
england bowler had complained about damp crease at warner park .
ground staff placed sand on the crease but broad slipped over next ball .
he required lengthy treatment on the field and an ice pack off it .
broad should be able to continue in practice match with st kitts team .
england loaned their hosts trott , ballance and bairstow for more practice .
trott was out for a duck off the bowling of team-mate james anderson .